A follow-up study on the development of the factors that have effects upon gaining ball speed in kicking motion

本研究旨在探讨静止与开球两种不同球况下，影响踢球动作中球速获得因素的相对发展，结果如下：1.球速随年龄增长而显著增加，且与挥杆速度呈高度相关。其他变化显著的因素有挥杆速度、静止球时踢球角度、击球时摆动腿侧上肢最大角度、击球时踢球侧上肢角度、膝关节角度范围和触球位置。将腰部置于球后并向后倾斜，使膝盖更容易伸展，这是踢球的特征之一。蹬伸腿和枢腿侧上肢的动态运动可以作为幼儿蹬伸运动的有效指标.在9 ~ 11岁阶段，静止球的踢球角度和触球位置有显著的进步。说明他们能用脚背踢球，技术因素对获得球速的影响较大。5.在10 ~ 12岁年龄段，胫骨前肌在触球前后均表现出较强的放电。这表明，肌肉力量也影响获得球的速度。

The purpose of this study is to investigate the relative development of the factors that have effects upon gaining ball speed in kicking motions under two different ballconditions : stationary and tee-up.The results are summarized as follows.1.Ball speed was increased remarkably with age and showed high correlation between swing speed.2. Other factors that showed remarkable change were swing speed, angle of the kicked ball in stationary ball, maximal angle of upper limb of pivot leg side in kicking angle of upper limb of kicking leg side at impact, range of knee angle and the position of ball contact.3.In infancy, positioning his waist behind the ball and leaning backward make it easier to extend the knees and this movement is one of the characteristic of ball kicking. Dynamic movement of kicking leg and upper limb of pivot leg side would be effective indexes of kicking motion in infancy.4. At the stage of 9 to 11 years of age, angle of the kicked ball in stationary ball and the position of ball contact progresed remarkably. It suggests thet they can kick by instep and the technical factor has higher effect on gaining ball speed.5.At the stage of 10 to 12 years of age, the tibialis anterior showed strong discharge before and after the ball contact. It suggests that muscular strength also effects on gaining ball speed.